This proposal is a request for a Research Career Award (K02) which would provide the applicant the means to further his career development by dedicating himself to research on the biochemical effects of alcohol at the level of the cellular membrane. In particular, the applicant plans to examine the effects of ethanol on cellular signaling and the effects of ethanol on membrane structure. Acute and chronic ethanol exposure is known to interfere with polyphosphoinositide signal transduction. Acute ethanol exposure disorders membranes, whereas chronic ethanol exposure promotes an adaptive homeostatic response to the acute disordering effects. In microsomes, the adaptive response is accentuated in the phosphatidylinositol (PI) fraction of phospholipids. Linking these two ethanol sensitive processes is phosphatidylinositol transfer protein (PITP). PITP is an obligatory requirement for polyphosphoinositide signaling and for a variety of vesicular trafficking events. It transports PI from the endoplasmic reticulum or Golgi to the plasma membrane. We have found that the activity of phosphatidylinositol transfer protein (PITP) is enhanced by the presence of clinical concentrations of ethanol or chloroform. We found that PITP activity is exquisitely sensitive to membrane structure (curvature) in ethanol's absence-PITP's sensitivity to membrane order was previously established. This proposal is aimed to elucidate the role of ethanol, PITP, and membrane structure in signal transduction processes. The effects of acute and chronic ethanol exposure upon phospholipid (phosphatidylinositol) mediated by the phosphatidylinositol transfer protein will be investigated. Interference with the binding, transfer and incorporation of newly synthesized phosphatidylinositol into inositol lipid signaling pathways in the plasma membrane by acute or chronic ethanol exposure is likely to alter phosphatidylinositol 4,5-bisphosphate dependent processes. The relationship between domain formation and the effects of ethanol on phosphatidylinositol transfer activity will be investigated. The acute and chronic effects of ethanol on the intrinsic membrane curvature, the ability of the membrane to bind alcohols, and the disordering efficacy will be contrasted within the context of signal transduction.